Effect of Necrotizing Enterocolitis on Growth and Development in Preterm Neonates

Abstract

Necrotizing enterocolitis (NEC) is a potentially disastrous illness in preterm neonates with significant mortality and morbidity including need for surgery, prolonged dependence on parenteral nutrition, and survival with short bowel syndrome and its consequences. The incidence of NEC has not changed significantly despite the recent advances in neonatal intensive care. However, the improved standard of care means the absolute number of survivors of NEC has increased. Long-term growth and neurodevelopmental impairment in preterm, especially extremely low birth weight, neonates needing surgery for the illness is a significant issue. Systematic reviews of observational studies indicate that the risk of long-term neurodevelopmental impairment (NDI) is significantly higher in preterm very low birth weight (VLBW) neonates with ≥ Bell Stage II NEC vs no NEC (OR: 1.82; 95% CI: 1.46–2.27), and those requiring surgery are at a higher risk for NDI vs those managed medically (OR: 1.99; 95% CI: 1.26–3.14). Inflammatory cytokines like tumor necrosis factor alpha and platelet activating factor play an important role in the pathogenesis of NEC and sepsis, which are often associated with each other. Prolonged exposure of an immature and vulnerable brain to high levels of inflammatory cytokines, recurrent bouts of sepsis, and suboptimal nutrition during the critical early postnatal period explain the adverse effects on growth and neurodevelopment in survivors of surgical NEC. Despite decades of research the pathogenesis of NEC continues to remain poorly understood. Prevention of prematurity, the single most important risk factor for the illness, is difficult. However, antenatal glucocorticoids and preferential feeding with breast milk have been consistently shown to reduce the risk of NEC significantly. Prophylactic probiotic supplementation also significantly reduces the risk of NEC and all-cause mortality while facilitating feed tolerance in preterm VLBW neonates. Secondary prevention is equally important as almost all of the morbidity including long-term impairment of growth and neurodevelopment is faced by those in whom NEC progresses to a stage needing surgery. Early diagnosis, prompt surgical intervention, and an aggressive approach to management of sepsis and provision of optimal nutrition may minimize the adverse effects of NEC on growth and neurodevelopment of preterm neonates.